A wind-shield blind system patented by U.S. Pat. No. 5,054,533 comprises a roller blind carried by a roller blind mechanism having a ratcheting mechanism which allows the roller blind to extend only and prevents it from being accidentally rewound so as to lock the roller blind stationary with respect to the roller at any of a plurality of positions along its extension. The roller blind mechanism can be released from the effect of the ratcheting mechanism by pressing a control stem to automatically rewind the roller blind.
But it has been found to have a disadvantage that the rotation of the roller is quite unstable, allowing the roller to rotate unexpectedly when it is in locked position.